Duplicate 2 Window for Firefox 4
Open new windows with the current URL!
This addon overrides the CTRL-N hotkey and opens the new windows with the current URL. Forked from Restartless Restart, thanks to Erik Vold!
The main audience of this extension is the (ex-)IE users who need this new-window behaviour.
The secondary / Mercurial repository is at http://code.google.com/p/duplicate2window/ if you don't like hg-git.